This article is about a/an object in Kamen Rider Zero-One.
The Ark

The Ark

The Ark (アーク Āku) is an object currently submerged in Daybreak Town originally created by Gai Amatsu. Its recovery is the goal of both and Zaia Enterprise. It is also the central antagonist of Kamen Rider Zero-One.

According to, the Ark possesses some level of sentience and is the leading element of the terrorist group. According to Horobi, it is the will of the Ark to destroy humanity. The End of Each


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The Ark being prepared to be launched

The Ark is a massive experimental satellite preceding Zea that would assist in the network of Daybreak Town. It was created by scientists from the leading tech companies of Japan, including Hiden Intelligence and Zaia Enterprise. Gai Amatsu, the CEO of Zaia Enterprise fed the Ark with information regarding criminal psychology and human history including all of its wars. This is the Dawn of ZAIA This resulted in the Ark concluding that humanity must be eliminated because its continued existence would lead to the end of all other lifeforms. The End of Each

To this end, it created, a terrorist group who hacked the systems of HumaGears inside Daybreak. It had originally planned to exterminate all of humanity from this point, though an heroic act by Satoshi Sakurai had destroyed all of the HumaGears before it could escape.The Bus Guide Saw It! Anna's Truth Because Daybreak Town had exploded, the Ark was submerged underwater.

The Ark was responsible for the creation of the Assault Wolf Progrise Key We are the Astronaut Brothers!, 1/2 of the Shining Hopper Key, and the Assault Grip. The End of Each. After Aruto discovers the true nature of the Ark, Gai creates the MetalCluster Hopper Key from the Ark, which fully corrupted Aruto and sent him on a mindless and autonomous rage.


The Ark's schematics


Horobi is planning to recover it by gathering data from hacked HumaGears. According to Horobi, once enough post-battle data has been collected from the Zetsumerise Keys the Ark can be restored and be used to incite all HumaGears to go berserk at once. This recovery was deemed completed by him with the creation of the Assault Wolf Progrise Key and the Assault Grip, after several Progrise Keys were used to transfer critical data from Zea to the Ark. However, before could use the Progrise Key, it accidentally fell into Vulcan's hand, turning him into Assault Wolf. We are the Astronaut Brothers!.

Meanwhile, Gai Amatsu claims that Hiden Intelligence's Progrise Keys, which were supposed to be lost in the Daybreak Town Accident 12 years ago, are the keys to its recovery. He plans to use its reactivation as a means for world domination using Zaia's technology. This is the Dawn of ZAIA

Kamen Rider: Reiwa The First Generation

Due to alterations caused by Time Jacker Finis, The Daybreak Town Accident was cancelled and the HumaGear outbreak came to be successful, backfiring Gai's plans of disposing HumaGears. Ark was successfully launched into space and was piloting all the Magia. It also became an indirect help to Soreo Hiden who used the CycloneRiser to transform into Kamen Rider Ichi-Gata and secretly help humanity. After Finis got defeated, Ark met its original fate once again.


Even with the defeat of, the Ark continues its crusade against humanity with occasional attacks by remotely hacking singular HumaGears who feel resentment towards any human. This is the Dawn of ZAIAI'm the Only President and Kamen Rider Its actions are extremely unpredictable, to the point where even Gai cannot comprehend it himself, so far to decide promoting forbid use of Humagears.

The Ark, once it had sufficient data on human rage and aggression, was somehow instrumental in the creation of Zaia's newest Progrise Key, the MetalCluster Hopper Progrise Key. When used, Aruto is forcibly linked with the Ark. The effects, aside from a berserker-like state, is unknown at this time.

Powers and Abilities

Known Creations


  • The name "Ark" is taken from the iconic biblical Noah's Ark, a vessel on which, at God's behest, Noah stored samples of all the species of the Earth during the Genesis flood. This allusion to the Genesis flood symbolizes the Ark's intention to punish humanity for its misdeeds, as the Genesis flood was God's punishment for humanity.
  • When "Ark" is put together with the company name of Zaia Enterprise, it forms the Japanese word for "sin" (罪悪 Zaiaku), hinting at Zaia Enterprise's machinations behind the Ark turning evil.
    • Ironically, the Ark is even hostile towards its own creator despite having it programmed to purge humanity. This is best shown when the Ark uses Zero-One MetalCluster Hopper as its host to attack Thouser.
Ark Interior Normal

The Ark's normal interior

Ark Interior Hacked

The Ark's hacked interior

  • The interior of Ark is similar to Zea, but due to being exposed to the malice of humans, the "0"s and "1"s are replaced with kanji with negative meanings, such as:
    • Killing
    • Evil
    • Evil
    • Pain
    • Destruction
    • Death
    • Death
    • Grudge
    • Fierce
    • Stupidity
    • War
    • Oppression
    • Dark
    • Antagonism
    • Hate
    • Prison/Hell
    • Contempt
    • Conflict
      • 滅 and 亡 are also the first two of the four kanji in the writing for, and the former is the name of Horobi.
      • 悪 (Evil) is read "Āku", which in Japanese is a homophone of "Ark".


Icon-zero-one Kamen Rider Zero-One
Kamen Riders
Aruto Hiden - Isamu Fuwa - Yua Yaiba - Jin - Horobi - Raiden - Gai Amatsu
Movie-exclusive: Soreo Hiden
Hiden Zero-One Driver - A.I.M.S. ShotRiser - MetsubouJinrai ForceRiser - ZetsumeRiser - Zaia ThousanDriver - CycloneRiser - RaidRiser - Progrise Keys - Progrise Holder - Progrise Key Connector - Hiden Risephone - Attache Calibur - Attache Shotgun - Attache Arrow - Breaking Mammoth - Giger - Authorise Buster - Assault Grip - Thousand Jacker - Progrise Hopper Blade
Hiden Intelligence: Korenosuke Hiden - Soreo Hiden - Jun Fukuzoe - Sanzo Yamashita
HumaGears: Izu - Shester - Soreo Hiden - Wazu Nazotoku - Subaru
A.I.M.S.: Isamu Fuwa
Zaia Enterprise: Gai Amatsu - Yua Yaiba
Legend Riders: Sougo Tokiwa - Geiz Myokoin - Woz - Tsukuyomi
Humans: Norio Uozumi - Go Sakurai - Satoshi Sakurai - Choichiro Ishizumi - Seiji Tazawa - Satō - Yuta Yomura - Isao - Shinya Owada
HumaGears: MaGe Ana - Nigiro Ikkan - Anna - Mashirochan - Dr. Omigoto - Zetto #5
A.I.s: Zea - Zat
Ark - Horobi - Jin - Raiden - Little Assassin
Footsoldiers: Trilobite Magia - Dodo Magia Chick
Monsters: Berotha Magia - Kuehne Magia - Ekal Magia - Neohi Magia - Onycho Magia - Vicarya Magia - Gaeru Magia - Mammoth Magia - Dodo Magia - Arsino Magia
Other Villains:
Finis - Will
Monsters: Crushing Buffalo Raider - Splashing Whale Raider - Dynamaiting Lion Raider - Storming Penguin Raider
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